My last shocks I couldn't get enough torque on the torx bit to loosen the bolt with a ratchet. Ended up taking it to my friend's shop. He used a pipe wrench around the head of the bolt to get it and and put it back. Sounds so dang simple, but it worked. The torx star was stripped some, that is why he used the pipe wrench.
the brake calipers are the same way on the discs and they take a T45. if they're stripped you'll need new ones, they end up looking like a 7mm allen head when they get stripped